344 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1907. 
is breaking over the dikes at the head of the Paradones and following 
this channel is making its way into Volcano Lake, whence some of 
the stream turns north into the Salton Sea. It is presumed, however, 
that only enough water will be taken directly from the Colorado 
River to irrigate the land of the farmers and that no water will come 
to the Salton Sea except that which escapes by seepage from the culti- 
vated areas of Imperial Valley. 
EVAPORATION FROM THE SALTON SEA. 
Assuming that the direct flow of the Colorado River can be 
checked and that no water comes indirectly through Volcano Lake, 
it is possible to use the Salton Sea as a great evaporating pan 
for the measurement of the amount of evaporation in this arid 
region. A knowledge of this factor is very valuable in establish- 
ing data upon which to place estimates of the amount of water 
which may be lost from reservoirs and other hydraulic works. The 
Weather Bureau is therefore attempting to utilize the Salton Sea 
for this purpose, and with a knowledge of the amount of water which 
is passing into the sea and by making corresponding deduction is not- 
ing from day to day the net evaporation or loss of water from the sur- 
face. Very delicate observations are being made of the humidity, 
rainfall, temperature, and other factors which influence the amount 
of evaporation. 
FUTURE HISTORY. 
It is assumed that the area of the sea will rapidly contract and 
that its waters will fall by loss through evaporation at a rate of 
5, 6, 7, or more feet per year. The precise rate as above stated 
is one of the things on which more definite information is needed and 
one which will require careful observation and study to eliminate the 
conditions which disturb accurate measurements. 
For many years, however, the sea will probably be a landmark of 
great interest to the overland traveler, and while it has no discerni- 
ble influence upon the climate in general, it will serve to ameliorate 
the condition of overland travel through the desert. After the long 
hot ride, it is very refreshing to skirt the shore of the Salton Sea 
(Pl. TX) and glide along in the train beside the little sandy beaches 
or across the arms of the sea spanned by railroad bridges. 
The water near the inlet has been relatively sweet, and fish from the 
Colorado River have come down as far as the lake. The great body 
of water, however, is distinctly saline or brackish and, as evapora- 
tion proceeds, will become more and more salty. It is a matter of 
conjecture, however, as to whether the sea will ever within the life- 
time of anyone now living return to its former small dimensions or 
will afford again a field for the manufacture of salt, 
